(ISC)2 Certified in Cybersecurity Practice Exam

Which component of the operating system resides in memory at all times?

1. User Interface

2. System Logger

3. Kernel

4. File Manager

The correct answer is: Kernel

The kernel is the core component of an operating system that remains in memory at all times while the system is running. It serves as the bridge between applications and the hardware, managing system resources, including CPU scheduling, memory management, and input/output operations. The kernel operates in a privileged mode, ensuring that user applications do not directly interact with the hardware, which adds a layer of security and stability to the system. Being constantly resident in memory allows the kernel to efficiently respond to requests from applications and handle system calls effectively. Other components, such as the user interface, system logger, and file manager, may be loaded into memory when needed, but they can also be unloaded or allowed to reside in secondary storage when not in use, unlike the kernel, which is essential for the ongoing operation of the operating system as a whole. This persistent presence of the kernel is critical for maintaining the system's functionality and performance.